The present invention relates to a new and improved method of, and apparatus for, cooling a strand during the continuous casting of metals, especially steel, wherein a cooling fluid or coolant having a regulatable quantity for impinging the strand surface is sprayed between two guide elements neighboring one another in the direction of travel of the strand onto the strand surface.
It is already known in this particular field of technology to turn-on and turn-off the nozzles of individual nozzle blocks in order to accommodate the cooling conditions for the strand to the casting parameters, such as for instance casting speed. With this technique there is indeed realized a certain regulation possibility, but there must however be accepted irregularities as concerns the impingement of the strand surface with the cooling fluid or agent and the cooling over the strand width. When turning-off the cooling fluid, typically cooling water, of a row of nozzles extending transverse to the strand axis the spacing between the upper and lower nozzle rows neighboring the turned-off nozzle row in the direction of travel of the strand and the corresponding impingement surfaces at the strand, respectively, becomes so large that there can occur fissures or cracks in the cast product or casting. There is likewise not contemplated a reduction in the supporting distance of the guide elements.
It is further known to the art for the purpose of producing cooling agent spray patterns or fans to have at least two flat spray patterns intersect one another at a location spaced from the surface of the strand, wherein at least one of the flat spray patterns deviates in its direction from the perpendicular impinging at the strand surface. The distribution of the quantity of cooling agent is such that from the center of the strand towards the edges thereof lesser quantities of water are sprayed onto the strand surface. With this proposal the relevant flat spray nozzles are adjusted at an angle with respect to one another, so that there is realized an overlapping of the spray patterns. In this way there is realized an increased width of the impinged surface. Yet, due to the overlapping or intersection of the spray patterns or jets it is well known in this art that there arises a mutual disturbance or interference of the spray patterns as well as in consequence thereof irregular cooling. Furthermore, both the kinetic energy of the cooling agent particles and the cooling action are reduced.
There is also known to the art a flat spray pattern nozzle for producing two narrow spray patterns. However, this nozzle is arranged such that the two spray patterns impinge at the edge region at neighboring strand sides without mutual contact.